Presentations are a fundamental part of business, from customer presentation to employee briefing. Those that have been formally trained as executives or as speakers can draw on large amounts of experience and can give slick, well structured presentations. Members of staff whose line of work is not primarily customer facing, however, do not receive the same level of training, which can result in shaky, nervous delivery, poor time management, and an overall apparent lack of professionalism, despite actually having an excellent knowledge of the subject matter being presented.